import math

class A:
    def __init__(self,x,y):
        self.x=x
        self.y=y


class B():
    def __init__(self,p1,p2):
        self.x = p1.x - p2.x
        self.y = p1.y - p2.y
        self.len = math.sqrt(self.x*self.x + self.y*self.y)

    def getlen(self):
        return self.len

p1 = A(1,1)
p2 = A(4,5)
line= B(p1,p2)

